Combined electrical and fluid rotatable connector



March 17, 1964 J. A. ST. CYR

COMBINED ELECTRICAL AND FLUID ROTATABLE CONNECTOR Filed Oct. 25, 1960 INVENTOR. I JOSEPH /4. 5x 634?.

United States Patent 3,125,649 COMBINED ELECTRICAL AND FLUID ROTATABLE CONNECTOR Joseph A. St. Cyr, 6 Golf Road, Wethersfield 9, Conn. Filed Oct. 25, 1960, Ser. No. 64,860 4 Claims. (Cl. 2llil--82) This invention relates to an electrically conductive rotatable connector and more particularly to a rotatable connector for conducting electricity and a fluid such as compressed air or gas.

The rotatable connector provided by my invention is particularly well-suited for use with metal working tools such as welding or cutting torches. Such tools are generally connected to a heavy conduit through which electricity and a gas are supplied thereto. The weight of the conduit, coupled with its inherent stillness, sometimes makes manipulation of the tool extremely difficult and it is desirable to insert a rotatable connector in the conduit adjacent the tool to facilitate movement thereof. Rotatable connectors are presently available for this purpose, but they are subject to leakage and, in particular to arcing which soon impairs their efliciency.

The primary object of this invention, therefore, is to provide a non-arcing rotatable connector for conducting electricity and a fluid which is also highly resistant to leakage.

A further object of this invention is to provide a rotatable connector in which the electrical connection is made through a confined body of mercury to prevent arcing between the relatively rotatable parts of the connector.

Another object of my invention is the provision of a rotatable connector which is operable in response to the pressure of the fluid therein to control the flow of electric current.

A still further object of my invention is to provide a rotatable connector which functions to break the electric circuit therethrough in response to an increase in the pressure of the fluid therein.

Further objects and advantages of this invention will be more clearly understood from the following description and accompanying drawing in which:

FIG. 1 is a sectional elevational view of a conventional metal working tool having my improved rotatable connector mounted therein.

FIG. 2 is an enlarged sectional elevational view of said rotatable connector in its normal condition.

FIG. 3 is a similar View illustrating the operation of the connector.

FIG. 4 is a sectional end view on line 44 of FIG. 3.

In FIG. 1 of the drawing I have shown, by way of example only, my improved rotatable connector mounted in a conventional metal-working tool. Said tool, generally indicated at 5, comprises 'a handle6 of dielectric material having a tubular nozzle 7 mounted therein. Said nozzle 7 includes a gas'tube 8 which is adapted to receive an electrode 9, and a shell 10 which is disposed concentrically with respect to the tube 8 form a gas passage therebetween communicating with the tube 8 through openings 11-11 therein. "Avalve casing 12 is contained in the handle 6 and 'isthr'eade'd to'the nozzle 7. Said casing carries'a normally closed valve 13 which is adapted to be moved to open position by a depressible operating member 14 to permit the passage of air or a gas to the nozzle 7.

The rotatable connector of the present invention, indicated at 15, is contained in the handle 6 and is secured at one end to the valve casing 12 and at its opposite end to a flexible conduit 16. Said conduit comprises a fluid conducting tube 17 of dielectric material having an electrically conductive outer covering 18 which is connected to a supice ply conductor 19. A tubular shield 20 of dielectric mate rial covers the tube 17 and the conductor 18.

In accordance with the present invention, the rotatable connector 15 comprises an outer cylindrical casing 21 of electrically conductive material such as brass, bronze or copper. Said casing 21 is open at one end and at its other end has an axial tubular extension 22 which, in this instance, is externally threaded for securing the connector to a separate member such as the valve casing 12. A tubular inner sleeve 23 is slidably and rotatably mounted in said casing 21. Said sleeve 23 is also made of electrically conductive material and includes a piston portion 24 and a shank portion 25 which is of reduced diameter. The bore 26 of said sleeve is coaxial with the bore 27 in the extension 22 of the outer member to provide a direct passage for fluid through said connector.

The piston portion 24 of said sleeve 23 has an annular groove therein which provides an annular chamber 28 between said piston portion and said outer casing 21. Said chamber is filled with an electrically conductive liquid 29, such as mercury, which provides a positive electrical connection between the sleeve 23 and the outer casing 21 of said connector while permiting relative rotation thereof without arcing. The conductive liquid 29 is sealed in the chamber 28 by means of suitable packings such as 0- rings 303tl which are contained in annular grooves in said piston portion 24 at opposite sides of said chamber 28 and slidably and rotatably engage the wall of the bore in the outer casing 21. v

The entire peripheral surface of the inner sleeve 23 is spaced from the wall of the bore in the casing 21, and said sleeve is supported for sliding and rotational movement therein by piston rings 31 and 32 which are affixed to said sleeve at the opposite ends of the piston portion 24 thereof. Said piston rings 31 and 32 are made of dielectric material and therefore provide electrical insulationbetween the sleeve 23 and the casing 21. The piston ring 32 is provided with a tubular portion 33 which extends over the shank 25 of the inner sleeve and form-s an insulating shield therearound.

The inner sleeve 23 is normally yieldingly maintained in its innermost position in the outer casing 21, as shown in FIG. 2 by a compression spring 34. Said spring surrounds the shank 25 of said sleeve 23 and has one end bearing againstthe piston ring 32 and its opposite end bearing against a retaining ring 35 which is mounted in an annular groove 36 in the inner wall of the casing 21. It will be seen that the spring 34 is insulated from the sleeve 23 by the piston ring 32 and by the insulating shield 33.

In accordance with my invention, a tubular insulating sleeve 3-7 of dielectric material is mounted in the wall of the bore in the casing 211 with its inner surface substantially flush with the surface of said wall. Said insulating sleeve 37 is located so that its inner end is disposed closely adjacent the chamber 28 containing the mercury 29 when the inner sleeve 23 is in its normal position as shown in FIG. 2. t

It will also be noted from FIG. 2 that the piston ring 31 at the inner end 38 of the sleeve 23 is bevelled slightly and normally spaces said inner end 38 of the sleeve from the inner end 39 of the bore in the casing 2 1. This arrangement provides a fluid chamber 40 between the sleeve 23 and the casing 21 for a purpose to be later described.

When my improved connector is used in the manner shown in FIG. 1, it is connected to the conduit 16 by a suitable fitting 41; the outer end of the sleeve 23 being threaded, as at 42, to receive said fitting. The fitting 41 is adapted to receive the fluid conducting tube 17 and to provide electrical contact between the conductor 18 and the sleeve 23. When the valve 13 is opened by depressing the operating member 14, the spring 34 urges the inner sleeve 23 of the connector to the position shown inFIG. 2 and air or gas supplied through the tube 17 passes through said fitting 41 and the bores 26 and 27 of'the connector to the nozzle 7 from which it is ejected around and adjacent the tip of the electrode 9 and directed against the work during a welding or cutting operation. The electric current for energizing the electrode passes through the conductor 18, the fitting 41, the inner sleeve 23, the mercury 29, the outer casing 21 the valve casing '12 and the tube Sto the electrode 9. When the tool is rotated, the casing 21' will rotate relatively to the sleeve 23 to facilitate manipulation of the tool, and the mercury will prevent arcing because of its intimate contact with the walls of the chamber 28.

When the valve 13 is closed, the pressure of the air or gas in the chamber 40. of the connector immediately increases and forces the sleeve 23 rearwardly, against the force ofthe spring 34, to the position illustrated in FIGS. 3 and4; In this position of said sleeve, the mercury 29 is in engagement with the insulating sleeve 37 and the flow of electric current from the sleeve 25 to the outer casing 21 is therefore prevented. When the valve 13 is again opened, the pressure within the connector drops and the sleeve 23 will then be urged forwardly under the influence of the spring 34 and will carry the mercury into electrical contactwith the outer casing 21, as in FIG. 2, to permit the flow of electric current from the inner sleeve to the outer casing 21. Thus, the electrode 9 is energized at' the same time that air or gas is supplied to the elec-v trode from the nozzle 10-. When the valve is again closed, the pressure will build up Within the connector and force the inner member to its rearward position, as shown in FIG. 3, and thereby de-energize the electrode.

From the above description it will be understood that my invention provides an improved connector which cooperates to automatically break an electric circuit in response to an increase of pressure therein, when the flow of a fiuid'therethrough is shut on, and to close said electric circuit upon the lowering of said pressure when the flow isresumed, thereby providing for the simultaneous control of both the fluidand the electric circuit by means of a single manually operable member.

I claim:

1. A combinedelectrical and fluid connector including a'tubular outer member of electrically conductive material having a bore therethrough, a tubular inner member of electrically conductive material slidable in sealing relation in said bore and forming a fluid tight passage extend-ing through said connector, stop means limiting move-. rnent'of said inner member between first and second positions, means yieldingly biasing said inner member toward one of said positions, electrical contact means on said inner and outermembers engageable in .said first position.

of said'inner member to establish a continuous current path through said members, insulating means so disposed on saidouter member'as to render said electrical contact means inoperative when said inner member is in said secondposition and thereby break said current'path through said members, said; biasing means yielding against a change in-pressure in said connector to cause said inner memher to automatically move from one of said positions to the other.

2. A combined electrical and fluid connector including atubular outer member of electrically conductive material-having a bore therethrough, a tubular inner member of electrically conductive material slidable in sealing relation in said bore, said inner member including a piston portion slidably engaging the wall of said bore and having a groove in its outer surface, an electrically conductive liquid material contained within said groove, stop means limiting movement of said inner member between first and second positions, means yieldably biasing said inner m mber toward one of said positions, said conductive liquid in said first position of said inner member establishing a continuous current path through said members, insulating means so disposed on said outer member as to render said conductive liquid inoperative when said inner member is in second position tothereby break said current path through said members, said biasing means yielding against a change in pressure in said connector to cause said inner member to automatically move from one of said positions to the other.

3. A combined electrical andfiuid connector including a tubular outer member of electrically conductive materialhaving a bore therethrough, a tubular inner member of electrically conductive material slidable in sealing relation in said bore and forming a fluid tight passage extending through said connector, stop means limiting movement of said inner member between first and second positions, means yieldingly biasing said inner member toward one of said positions, electrical contact means-on said inner and outer members engageable in said first position of said inner member to. establish a continuous current path through said members, an insulating sleeve in said bore so disposed as to render said electrical contact means inoperative when said inner member is in said second position and thereby break said; current path through said members, said biasing means yielding against a change in pressure in said conneotorto cause said inner member to automatically move from one of said positions to the other.

4. A combined electrical and fluid connector including a cylindrical outer member of electrically conductive material having. an axialv bore therethrough, a tubular inner member of electrically conductive material in said bore, and forming a fluid passage through said connector, said inner member having a piston portion and a shank portion,

piston rings of dielectric material at opposite ends ofsaid piston portion slidably supporting'said inner member for axial movement and rotation in said bore, said piston portion having an annular groove therein between said piston rings, an electrically conductive. liquid material within said groove in electrical contact with said outer member, a dielectric insulating sleeve extending over saidshank portion of the inner member, a coil spring surrounding said insulating sleeve, and normally urging said inner member to a forward position insaid bore wherein said liquid material is in electrical contact with saidouter member, said inner member being movable axially in said bore against the force of said springin response to an increase in fluid pressure in said passage, and-an insulating sleeve in the wall of said bore disposedto insulate said liquid material fromsaid outer member when said inner member is so moved.

References Cited in the file of this patent. UNITED STATES PATENTS Nov. 22, 1955 

2. A COMBINED ELECTRICAL AND FLUID CONNECTOR INCLUDING A TUBULAR OUTER MEMBER OF ELECTRICALLY CONDUCTIVE MATERIAL HAVING A BORE THERETHROUGH, A TUBULAR INNER MEMBER OF ELECTRICALLY CONDUCTIVE MATERIAL SLIDABLE IN SEALING RELATION IN SAID BORE, SAID INNER MEMBER INCLUDING A PISTON PORTION SLIDABLY ENGAGING THE WALL OF SAID BORE AND HAVING A GROOVE IN ITS OUTER SURFACE, AN ELECTRICALLY CONDUCTIVE LIQUID MATERIAL CONTAINED WITHIN SAID GROOVE, STOP MEANS LIMITING MOVEMENT OF SAID INNER MEMBER BETWEEN FIRST AND SECOND POSITIONS, MEANS YIELDABLY BIASING SAID INNER MEMBER TOWARD ONE OF SAID POSITIONS, SAID CONDUCTIVE LIQUID IN SAID FIRST POSITION OF SAID INNER MEMBER ESTABLISHING A CONTINUOUS CURRENT PATH THROUGH SAID MEMBERS, INSULATING MEANS SO DISPOSED ON SAID OUTER MEMBER AS TO RENDER SAID CONDUCTIVE LIQUID INOPERATIVE WHEN SAID INNER MEMBER IS IN SECOND POSITION TO THEREBY BREAK SAID CURRENT PATH THROUGH SAID MEMBERS, SAID BIASING MEANS YIELDING AGAINST A CHANGE IN PRESSURE IN SAID CONNECTOR TO CAUSE SAID INNER MEMBER TO AUTOMATICALLY MOVE FROM ONE OF SAID POSITIONS TO THE OTHER. 